Fabrication and Functionalization of 3D Printed Polydimethylsiloxane‐Based Microfluidic Devices Obtained through Digital Light Processing

Abstract

This work reports the preparation and 3D printing of a custom‐made photopolymer based on acrylate‐polydimethylsiloxane (PDMS), for the fabrication of complex‐shaped 3D printed microfluidic chips. By selecting and combining the proper materials during the preparation of the resins along with the freedom of design of light‐based 3D printers, 3D microfluidic PDMS‐like chips are obtained with excellent optical features, high chemical stability, and good mechanical properties. Furthermore, taking advantage of unreacted functional groups exposed on the sample's surface after the 3D printing step, the surface properties of the devices are easily and selectively modified during the postcuring step through UV‐induced grafting polymerization techniques, giving an added value to the printed devices in terms of surface treatment compared to conventional methods. The 3D printing of the PDMS‐based resins developed here may potentially transforms the fabrication methodology of PDMS microfluidic devices by decreasing manufacturing costs and time, allowing the production of complex‐shaped and truly 3D microdevices.

3D Printing of PDMS-Like Polymer Nanocomposites with Enhanced Thermal Conductivity: Boron Nitride Based Photocuring System

“…The rotational viscosity was evaluated imposing a shear ramp to the samples and observing their behavior ( Figure 3 a). Pure TRAD presents a Newtonian behavior with an already relatively high viscosity (~1 Pa*s) when compared with other common DLP printable formulations [ 43 , 44 ]. Nevertheless, a viscous monomer can help the shelf-life of the formulations; in our case the filled formulations resulted stable for at least 7 days.…”

“…ATR-FTIR analyses were also performed to confirm the efficiency of the cross-linking reaction. The signal peak at 1190 cm −1 , attributable to the double bond of the acrylated silicone, was used to make a comparison between the liquid formulations and the polymers obtained after different irradiation times (from 2.5 s to 10 s) [ 43 ]. Figure 4 a,b, as an example, report the spectra of the pristine silicone–acrylate formulation and for the same formulation containing 1 phr of BN during irradiation (TRAD and 1 BN in Table 2 ).…”

“…A typical liquid resin for light-based 3D printing is made of three main ingredients: (i) the oligomer/monomer, which is responsible of the final physical and mechanical characteristics of the printed structure, (ii) the photoinitiator, which induces the polymerization reaction and (iii) a dye or colorant which assures a good resolution [ 42 , 43 ]. By properly selecting the different formulation components and fillers, it is possible to tailor specific functional properties to the final 3D printed objects [ 44 , 45 , 46 , 47 ].…”

Fabrication Methods for Microfluidic Devices: An Overview

“…Hashimoto et al [ 157 ] have described an interesting direct ink writing (DIW) 3D printer for dispensing a fast-curing flexible silicone resin on different substrates to create microchannels. Roppolo et al [ 158 ] have reported 3D printing of photopolymer on the basis of PDMS towards fabrication of microfluidic devices, which can offer attractive optical, mechanical, and chemical stability features. There is increasing interest in development of 3D printing approaches that can allow use of multiple materials [ 159 , 160 ], which could be valuable for integrated valves, through a combination of rigid and flexible materials with different shore values, or integrated electrodes for electrochemical detection or fluid driving purposes.…”

Vat Photopolymerization 3D Printing of Advanced Soft Sensors and Actuators: From Architecture to Function

“…Various resins were functionalized by adding fillers, and commercial resins were modified to be photocurable by selecting and combining appropriate photoinitiators and light absorbers. [ 29 ] Notably, hydrogels, crosslinked 3D networks of highly hydrophilic polymers, are processable for VP and widely used in sensing applications not only due to their intrinsic excellent flexibility, biocompatibility, and selective permeability, [ 30 ] but also due to the potential of multifunctionalization, including high transparency, conductivity, tunable mechanical properties, and self‐healing ability. [ 31 ] Reasonable configuration allows full use of functional materials and structural materials in providing perception and flexibility.…”